namespace utils {
    std::vector<std::string> split(std::string &str, char delimiter) {
        std::vector<std::string> res;
        std::string::iterator st = str.begin(), ed = st;
        for (; ed != str.end(); ++ed) if (*ed == delimiter) {
            if (st != ed) res.push_back(std::string(st, ed));
            st = ed + 1;
        }
        if (st != ed) res.push_back(std::string(st, ed));
        return res;
    }
}
